1. Field of the Invention
The present invention relates to a bonding apparatus such as a die bonding apparatus, wire bonding apparatus, etc.
2. Prior Art
A bonding apparatus is equipped with a heating block that heats lead frames. In other words, before bonding is performed on lead frames, the lead frames are placed on the heating block which has been heated to a temperature of 150 to 500.degree. C.; and bonding is performed after the lead frames are sufficiently heated by the heating block. If for some reason the conveying out of the lead frames from the heating block is stopped, the lead frames are exposed to continuous heating; as a result, the lead frames may be deformed, or the semiconductor chips (also called dies or pellets) mounted on the lead frames may be damaged.
Such a failure of normal conveying of the lead frames may result from various reasons. Such reasons include repeated detection due to the generation of detection errors caused by lack of agreement in shape recognition and detection of positional deviations of the lead frames, power failure in the heater of the bonding tool which performs bonding, and (in the case of a wire bonding apparatus) damage to the capillary, faulty wire feeding, etc.
Conventionally, the above-described excess heating of lead frames is prevented by a heating block raising-and-lowering mechanism. This mechanism raises and lowers the heating block; and when normal conveying of the lead frames is interrupted, the heating block is lowered so that heating of the lead frames is stopped.
However, in the above mechanism, since the heating block is heated by a heater, the heating block raising-and-lowering mechanism needs to have a good heat resistance and durability. Furthermore, since the heating block raising-and-lowering mechanism raises and lowers a heavy heating block and is built into a frame feeder that feeds the lead frames, the heating block raising-and-lowering mechanism tends to be large and has an extremely complicated structure, resulting in high manufacturing costs. Moreover, since the heating block raising-and-lowering mechanism has a complex structure, considerable maintenance time is required for periodic maintenance.